/**
 * 
 */
var width = 500,  
    height = 500;  
  
//定义数据转换函数  
var tree = d3.layout.tree()  
    .size([width,height-200])  
//定义对角线生成器diagonal  
var diagonal = d3.svg.diagonal()  
    .projection(function(d){return [d.y, d.x]})  
  
//定义svg  
var svg = d3.select("body").append("svg")  
    .attr("width",width)  
    .attr("height",height)  
    .append("g")  
    .attr("transform","translate(40,0)")  
  
//读取json文件，进行绘图  
d3.json("asserts/syndrome.json",function(erro,root){  
    var nodes = tree.nodes(root);  
    var links = tree.links(nodes);  
  
    //画点  
    var node = svg.selectAll(".node")  
        .data(nodes)  
        .enter()  
        .append("g")  
        .attr("class","node")  
        .attr("transform",function(d){return "translate("+ d.y+","+ d.x+")"})  
    //加圈圈  
    node.append("circle")  
        .attr("r",4.5)  
    //加文字  
    node.append("text")  
        .attr("dx",function(d){return d.children?-8:8;})  
        .attr("dy",3)  
        .style("text-anchor", function (d) {return d.children?"end":"start"})  
        .text(function (d) {return d.name})  
  
    //画线  
    var line = svg.selectAll("link")  
        .data(links)  
        .enter()  
        .append("path")  
        .attr("class","link")  
        .attr("d",diagonal)   
})  